One of the main search criteria for finding nearby low-luminosity stars is their high proper motion. The global proper motion catalogues of Luyten, particularly the LHS catalogue (Luyten 1979) and the NLTT catalogue (Luyten 1979-80, Luyten & Hughes 1980) represent the most important sources for the identification of low-luminosity stars.
In fact, the proper motions of all 58 stars in the Catalogue of Nearby Stars (CNS3) of Gliese & Jahreiß (1991) which are within 5 pc of the Sun exceed 0.5 arcsec/yr. From about 280 stars within 10 pc, there is only one M dwarf with a proper motion below the NLTT limit of 0.18 arcsec/yr. Fleming (1998) used X-ray observations of the ROSAT All-Sky Survey to identify M dwarfs within 25 pc of the Sun that are missing from the CNS3. His aim was to find young stars with small space motions not present in proper motion catalogues. Gliese, Jahreiß & Upgren (1986) claimed that within 13 pc of the Sun the CNS3 should be complete for stars with (around spectral type M4). Fleming (1998) found five M dwarfs with the above conditions, which are not in the CNS3. But all of these stars are catalogued proper motion stars and just nobody ever measured the distance to them.
In the southern sky with the proper motion catalogues are known to be incomplete. Therefore, a new high proper motion survey was started (Scholz et al. 1999). The main aim of this survey is to complete the proper motion catalogues (with arcsec/yr) at fainter magnitudes and to carry out follow-up spectroscopy for the most interesting faint objects, particularly low-luminosity white dwarfs and late-type M dwarfs. Nevertheless, relatively bright stars (), so far not known to have large proper motions, were also found in this survey.
Here we present the discovery of a nearby late-type M dwarf identified with an X-ray source and showing emission lines in its optical spectrum.
© European Southern Observatory (ESO) 1999
Online publication: April 28, 1999